Virtual monochromatic imaging in dual-source and dual-energy CT for visualization of acute ischemic stroke

TL;DR

This study demonstrates that virtual monochromatic imaging with dual-energy CT can optimally visualize acute ischemic stroke by identifying specific energy levels that maximize contrast-to-noise ratio.

Contribution

The paper introduces a method to determine optimal virtual monochromatic energy levels for stroke visualization using dual-energy CT, based on phantom experiments.

Findings

Optimal energy levels for stroke visualization are around 67-72 keV.

CNR values are significantly higher between 65 and 75 keV.

Specific tube voltage and filter conditions enhance image contrast.

Abstract

We have recently developed a phantom that simulates acute ischemic stroke. We attempted to visualize acute-stage cerebral infarction by applying virtual monochromatic images to this phantom using dual-energy CT (DECT). Virtual monochromatic images were created using DECT from 40 to 100 keV at every 10 keV and from 60 to 80 keV at every 1 keV, under three energy conditions of tube voltages with thin (Sn) filters. Calculation of the CNR values allowed us to evaluate the visualization of acute-stage cerebral infarction. The CNR value of a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140 kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The CNR values of virtual monochromatic images between 65 and 75 keV were significantly higher than those obtained for all other created energy images. Therefore, optimal conditions for visualizing acute ischemic stroke were achievable.